Abstract: A technique for automatically identifying a semiconductor wafer (30) having bar code identification indicia (32) on the front surface (31) thereof. Reading of the code is achieved by rotating the wafer about an axis (34) perpendicular to its front surface (31); directing a beam of radiant energy (37) at the code (32) along a predetermined direction relative to the front surface (31); and sensing, while rotating the wafer, the reflected radiant energy (39) within a second predetermined angular direction relative to the front surface. The bar code used herein is preferably a modified or "stretched" bar code 39 formed on the front surface of the wafer, and having an aspect ratio (i.e., dimension of a space/dimension of a bar) ranging from 1 to 4 (FIG. 2).
November 21, 1983
Date of Patent:
April 29, 1986
AT&T Technologies, Inc.
Hibbert A. Duncan, Francis J. Ehret, Sherwin R. Kahn, Karen H. Kinney, Peter D. Parry
Abstract: Apparatus for automatically selecting a semiconductor wafer out of a wafer cassette, and identifying the selected wafer. The apparatus (10) comprises means for accessing a selected individual semiconductor wafer (11) out of a plurality of wafers within a cassette (12), an arm (27) coupled to the accessing means for lifting the selected wafer partially out of the cassette, and a driving member (33) contacting the edge of the selected wafer and rotating the wafer to expose a predetermined portion thereof. An optical reader (37) is positioned proximate to the driving member for identifying information stored in the predetermined portion of the wafer (FIG. 1).
Abstract: A semiconductor wafer pickup device (26) making use of vacuum and Bernoulli effect in order to hold the wafer (11) against the device and to minimize wafer contamination. The wafer pickup device comprises a centrally located Bernoulli orifice (32) and a plurality of peripherally located small tubular legs (38,39,40). In a first stage of a pickup operation, air is blown out of the Bernoulli orifice and out of the tubular legs. Next, vacuum is applied to the tubular legs while pressurized air is still blown out of the Bernoulli orifice. The combination of the Bernoulli effect with the suction at the vacuum legs locates the wafer in a position where the legs hold onto it. Then, the pressurized air is turned off thus leaving the wafer held only by the vacuum legs (FIGS. 2A, 2B).
Abstract: A hand (10) capable of simultaneously handling a plurality of articles (11) comprising a pickup head (15) having a plurality of vacuum pickup cavities (18), each cavity substantially matching the size and shape of the article to be handled. In one embodiment, the pickup head comprises a seal (26) positioned around an article-matching cavity (18) thereof and an opening (19) therethrough for communicating the cavity (18) with a vacuum chamber (20). In another embodiment, the pickup head comprises, positioned within its opening, a bellows (48) having a cylindrical sleeve (51) at one end and a planar flange (49) coupled to the vacuum chamber (20) by means of a seal (52) at its other end.
Abstract: A method for mounting one or a plurality of multilead components (25-28) on a circuit board (20) is herein disclosed. The method comprises the steps of loading a releasable template (32) with the component/components to be mounted, positioning the releasable template proximate to the board, releasing the component/components from the template onto the board such that each lead of each component is proximate to a corresponding aperture in the board, and imparting a vibratory motion (via 29 and 23) to the board thereby inserting the component/components into the board. Also disclosed are various embodiments of an apparatus for achieving this mounting method using a programmable robotic arm (FIG. 2).
December 2, 1982
Date of Patent:
July 16, 1985
AT&T Technologies, Inc.
Brian D. Hoffman, Steven H. Pollack, Barry Weissman
Abstract: A test probe for the testing of electrical circuits and circuit boards comprises a probe head (52) breakably coupled to an elongated probe arm (51). The breakable coupling is achieved by securing a first ring (63) to the probe arm and a second ring (60) to the probe head. The first and second rings may be respectively made of magnetic material and magnetizable material (or vice versa) thereby achieving a magnetic breakable coupling between the head and the arm. The probe head may comprise one or a plurality of probing pins (54,55) depending upon the type of circuit under test. The break-away feature of the test probe prevents any shearing of a solder connection as well as any damaging of the circuit boards, and/or of the probing pin or pins (FIG. 5).
Abstract: An ultrasonic technique for remotely inspecting a body is described. A transducer (14), capable of generating and detecting ultrasonic signals, is coupled to the body. An ultrasonic signal (A.sub.o) is launched by the transducer (14) into the body (e.g. 10, 11) and is reflected by any imperfection (e.g. 12) therein. The effects of variations of the transmission coefficient between the transducer and the body are substantially eliminated by intentionally cutting a predetermined calibration notch (22) into the body under test. The analysis of the reflected ultrasonic signals at the notch (22) and at any imperfection (e.g. 12) within the body gives an indication of the quality of the body independently of the transducer/body transmission coefficient.
Abstract: A high-speed, high-resolution testing circuit for both analog and digital circuit packs is described. The testing circuit, which employs data compression techniques, comprises a shift register (22) having an overall length selectively variable under program control, and an arrangement (18) for combining incoming data signals with feedback signals out of predetermined stages of the shift register. The positions of the feedback taps of the variable length shift register are selectively variable under program control (24,26).
Abstract: Herein disclosed is a noncontact, nondestructive method for monitoring the quality of a high energy weld, e.g., laser beam weld. In accordance with the proposed method, an acoustic sensor (32) is positioned at a distance from the welding zone (34) and picks up airborne acoustic emission signals (33) associated with the laser welding process. These acoustic signals, propagating through the air space between the welding zone (34) and the sensor (32), are detected and analyzed (36,37) to determine the quality of the weld (FIG. 3).
Abstract: An automatic pull tester and an acoustic emission system are herein combined to analyze the failure modes of lead frames bonded to integrated circuits. By using a discriminant analysis technique, a specific failure mode can be determined in real-time by first measuring up to five variables during the pulling operation. The five variables that may be measured comprise acoustic emission signals of a first amplitude (AE1), acoustic emission signals of a second amplitude (AE2), the time elapsed until failure (.DELTA.t), the number (n) of acoustic emission bursts above a first threshold, to the peak pulling force at failure (L.sub.max). Next, the variables measured are incorporated into a plurality of predetermined functions, each function corresponding to one failure mode (FM1 to FM5). The failure mode of the bond is determined by selecting the function having the highest value (FIG. 4).
November 30, 1981
Date of Patent:
November 29, 1983
Western Electric Co., Inc.
Min-Chung Jon, Vito Palazzo, George W. Sturm
Abstract: The attachment of leadless chip carriers to printed wiring boards by means of soldering techniques must provide for a spacing between the chip carrier and the board. Such spacing is required for cleaning the area under the chip carrier, protecting the underlying circuitry, and accounting for stresses which may develop due to thermal mismatch between the chip carrier and the board, and to board flexure. Herein disclosed is a lead (15) for semiconductor chip carriers comprising an elongated body of high melting point electrically conductive material, e.g., solder material. Also disclosed is a method for casting such a solder lead, and a method for attaching a plurality of cast solder leads (38) to a leadless chip carrier (20).
Abstract: In the manufacture of integrated circuits, it is often necessary to prepare dielectrically-isolated single-crystal silicon regions to be used as substrates in which various circuit elements may be formed. These regions or substrates are formed by attaching a single-crystal silicon wafer (1) having a dielectrically-coated surface (2) to a second single-crystal silicon wafer (3) by means of an intermediate metallic layer (4) positioned therebetween. Using a heating process, e.g., a thermomigration process also referred to as temperature gradient zone-melting (TGZM) technique, the metallic layer (4) is removed through the second silicon wafer (3). This method substantially eliminates any bending or warpage of the dielectrically-isolated substrate (FIG. 1).
Abstract: A pulse generator comprises a toroid (11) of a superconducting material such as Niobium on a glass or ceramic substrate (12). A cryogenic source such as liquid helium cools the toroid to within a few degrees of absolute zero and a perpetually circulatory current is set up in the toroid. A laser beam is fired at the toroid to cause localized heating and the resultant current drop due to the material resistance causes an output pulse to be induced in an adjacent current winding (14).
Abstract: The architecture of a conventional digital computer, for example, a microprocessor, is modified by interposing a multiplexer (31), a logic array (32) and a demultiplexer (33) between the instruction register (17) and instruction decoder (18). The logic array "scrambles" the bits in each instruction code; however, if the program to be run is priorly encrypted with this "scrambling" in mind, it will run normally. On the other hand, if the encrypted program is copied, the copied program will not run on an unmodified computer.